How do I determine if a medication is safe for a breastfeeding mother?

Have you ever been told you need to stop breastfeeding because you need medical testing or a medication? Or told that you cannot receive treatment until you are done breastfeeding? The good news is that most medications are compatible with breastfeeding, and for those few medications that are a safety issue there are usually acceptable substitutions. Although mothers are frequently told they need to stop breastfeeding (temporarily or permanently) to take a medication, this is rarely necessary.

According to Thomas Hale, RPh, PhD (Medications and Mothers’ Milk 2014, p. 7-12): “It is generally accepted that all medications transfer into human milk to some degree, although it is almost always quite low. Only rarely does the amount transferred into milk produce clinically relevant doses in the infant… Most importantly, it is seldom required that a breastfeeding mother discontinue breastfeeding just to take a medication. It is simply not acceptable for the clinician to stop lactation merely because of heightened anxiety or ignorance on their part. The risks of formula feeding are significant and should not be trivialized. Few drugs have documented side effects in breastfed infants, and we know most of these.”

These references are GOOD sources for information on medications and breastfeeding:

Medications and Mothers’ Milk by Thomas Hale, RPh, PhD, is our favorite reference book and is updated every two years. This inexpensive reference is a must-have for anyone working with breastfeeding mothers, or breastfeeding mothers who frequently need information on medications.

The InfantRisk Center (1-806-352-2519), headed by Dr. Thomas Hale in the US, has a phone helpline and additional information on medication use during pregnancy and breastfeeding.

The LactMed Database, a free online database maintained by the National Library of Medicine in the US, is a wonderfulonline resource for information on breastfeeding and medications. If your health care provider does not know about this resource, spread the word! They also have a free smartphone app that is very useful.

MotherRisk (1-877-439-2744), operated by the Hospital for Sick Children in Toronto, Canada, has a phone helpline and additional information on medication use during pregnancy and breastfeeding.

Drugs in Breastmilk (0844 412 4665), from The Breastfeeding Network in the UK, has a phone helpline and additional information on medication in breastfeeding mothers.

Talking to baby’s health care provider (in addition to your own doctor) is also a good idea. Baby’s doctor will generally know more about the effects of medications on infants and young children, and whether a medication is typically given directly to infants or young children. Your baby’s doctor will also be aware of any particular health concerns that your baby has with respect to a particular medication.

These references are NOT good sources for information on medications and breastfeeding:

It is not appropriate to use pregnancy risk categories (A,B,C,D,X…) to determine the risk of a drug to a breastfeeding mother and her baby, since the entry of drugs into human milk is quite different than the entry of drugs across the placenta during pregnancy.

It is not uncommon to see doctors using the Physicians Desk Reference for information on medications and nursing. This reference contains the package inserts from the pharmaceutical manufacturers. Almost across the board, they indicate that each medication should not be taken while pregnant or breastfeeding. The warning statements they use are designed to protect themselves from lawsuits. The information in the PDR is based on the manufacturer’s studies on the product, but not other studies that have been done. In general the manufacturers have done no studies on lactating women, and thus say that there is no information (even if studies have been done by others). Many doctors also have access to the USPDI (US Pharmacoepia Drug Information), which tends to have more accurate information than the PDR about studies done on the drug and available information about transfer into milk. If you don’t have access to the “gold standard” references (above) on medications and breastfeeding, this reference is generally a better choice than the PDR.

If someone suggests that you should stop breastfeeding while taking a certain medication, keep in mind that this is a cost-benefit decision– the information available on the medication is not the only thing you need to take into account.

When considering a medication (including herbal and other “natural” preparations) here are several factors to take into account:

Does the mother need this medication/treatment right now, or is it something that she does not need or can easily postpone until her child is older?

How old is the breastfeeding child? Is s/he healthy? Premature babies, newborns, and babies with health problems require somewhat more caution when it comes to the medications that the mother is taking; healthy older babies and toddlers are generally at a lesser risk since their bodies can metabolize medications more easily.

How much breastmilk does the child get? A child who is getting smaller amounts of breastmilk (a newborn in the early days before mother’s milk volume naturally increases, a baby or child who is eating other foods in addition to breastmilk and breastfeeds less often, etc.) will also be getting less of any medication that passes into breastmilk.

Is the medication in question one with a record of safely being given directly to babies and young children? The amount of the medication that passes into breastmilk will normally be significantly lower than that given directly to young children.

Avoid medications known to affect milk production.

Temporary weaning is a risk to the mother’s milk supply. Milk supply may be compromised since pumps do not provide the same stimulation to supply as does a nursing baby. For the rare times when temporary weaning is needed, see this information on maintaining milk supply when baby is not nursing.

Temporary weaning comes with a risk that baby will not go back to the breast. Some babies have a hard time returning to breastfeeding after temporary weaning, and unfortunately we do not know ahead of time which babies will have problems.

There are known risks of formula feeding, including allergy, increased illness, etc. Many of the risks of formula feeding are not apparent for many years.

Looking for good medication resources in languages other than English?

MotherRisk (1-877-439-2744), operated by the Hospital for Sick Children in Toronto, Canada, has a phone helpline and additional information on medication use during pregnancy and breastfeeding in both French and English.

e-lactancia(English language version), a free online database maintained by APILAM (Association for Promotion and Cultural and Scientific Research of Breastfeeding) in Valencia, Spain, is another wonderful online resource with information on breastfeeding and medications, phytotherapy (plants), homeopathy and other alternative products, cosmetic and medical procedures, contaminants, and maternal/infant diseases. Information is available in both Spanish and English.

Läkemedel och amning, from the Drug Therapeutic Committee and the Public Healthcare Services Committee Administration of Stockholm County Council, Sweden, has a free online database with information on breastfeeding and medications.

Teratologisk Information Service (09 4717 6500), from the Hospital District of Helsinki and Uusimaa, Finland, has a help line and information on medications during pregnancy and breastfeeding.